Enzymes like carbonic anhydrase lower the energy of activation that is needed to initiate a reaction.
Biologic enzymes work as catalysts to increase the rate of reaction. They do this by lowering the activation energy needed to initiate the reaction. This is usually performed by bringing the necessary reactants in close proximity to one another in the proper biologic conformation and increasing the stability of the transition state. The delta G of the reaction governs the direction of equilibrium. A negative delta G favors the creation of products, while a positive delta G favors the creation of reactants.
Mckenna and Suparan discuss the new class of drugs known as carbonic anhydrase inhibitors. They state that these drugs can be used to treat glaucoma, cancer, obesity, epilepsy and infection. Inhibition of carbonic anhydrase prevents the conversion of carbon dioxide and water to carbonic acid thus affecting the blood pH.
Illustration A is a diagram displaying the change in free energy of a reaction and the effect of an enzyme in lowering the activation energy.
Answer 2: Enzymes do not alter these characteristics of a reaction. They only increase reaction rate by lowering the energy of activation.
Answer 3: Raising the activation energy would make it less likely for the reaction to occur.
Answer 4,5: The free energy of products and reactants is determined by the chemical nature of the molecule and is not altered by enzymes.
McKenna R, Supuran CT. Carbonic anhydrase inhibitors drug design. Subcell Biochem. 2014;75:291-323.
PMID:24146385 (Link to Abstract)